LC-MS based metabolomic approach applied to bioactive molecules identification: case study of a comprehesive chemodiversity screening of Viola genus
Résumé
The objective of this study, part of the Viola tolosa project, was to evaluate the chemical potential of Viola genus samples without impacting the bioresource1. Therefore, a metabolomics approach was used to obtain a comprehensive screening of the collection of violets from the French Violet Conservatory hosted by the Toulouse Municipal Greenhouses. Focussed on the non-volatile compounds of leaves, this approach involved multivariate analysis of LC-MSE high resolution profiles of total extracts along a parallel screening of their antioxidant activities. Then, the dereplication of putative active compounds was obtained by correlation analysis presenting two main benefits: a limited amount of crude material and restricted time consuming manipulations. The relevance of this approach was established by TLC-DPPH assays of extracts and subsequent identification of DPPH active spots using a TLC-MS interface. The first results on Viola alba subsp. dehnhardtii aka Violet of Toulouse, highlighted the presence of antioxidant polyphenols never characterized in this genus. The results obtained will permit the assessment of the chemodiversity of the violet collection based on metabolite analysis and future identifications of potentially biologically active extracts or molecules for further dermocosmetic valorizations. Combined with future analysis of native volatile compounds emitted by fresh flowers by SPME-GC-O-MS, this holistic approach should provide a comprehensive chemotaxonomy of violets.